1. Field of the Invention
This invention relates generally to a shock attenuating apparatus, and more specifically to an improved automatic closure device for a liquid shock attenuating apparatus.
2. Description of the Prior Art
This invention is related to and an improvement of the invention described in U.S. Pat. No. 3,572,465 issued Mar. 3, 1971 to William Carl Olson for a Liquid Shock Attenuating and Preventing Device, the disclosure of which is incorporated by reference herein. That patent taught a shock attenuating device that may be adapted for use on, or in connection with automobile bumpers, roadway guardrails and the like. U.S. Pat. No. 3,572,465 described a device in which impact is attenuated by a hollow resilient elongated one-piece body formed by a substantially flat reinforced rear wall, a top wall and front, side and bottom walls defining a cavity which is filled with water. A plurality of apertures are provided in the top wall, each of which apertures is defined by resilient walls and is closed by a resiliently deformable plug in frictional engagement with the aperture walls. In response to a strong impact against the front wall of the body, a series of physical steps occur which result in ejecting the plugs from, followed by water from the cavity upwardly through, the apertures.
However, in this arrangement, the plugs are left outside the apertures after ejection. This is not only aesthetically unsightly, but also leaves the plugs exposed to damage or removal. Furthermore, the apertures are left open, thereby obviating the systems ability to attenuate a subsequent impact (as in a chain-reaction accident).